In prior art telecommunication switching systems that communicated a large number of calls, the reliability of the telecommunication switching system has always been a major problem. Within the prior art, the solution to this reliability problem has been to fully duplicate the system so that there is an active switching system and a standby switching system. If a failure occurs in the active telecommunication switching system, then, the standby telecommunication switching system will commence to communicate the active calls. Normally, the standby telecommunication switching system performs this operation with minimal disruption of active calls.
Whereas the prior art telecommunication switching systems did provide a solution, this solution has many problems. The first problem is that the full duplication of the switching fabric adds a great amount of cost and complexity to the resulting system. Second, the added reliability achieved by having a fully duplicated system is not as great as would be desired. The reason is that it takes one failure to disable the active switching network and only a second failure to disable the second switching network. The result is that two failures can cause a total failure of the telecommunication switching system. Third, prior art telecommunication switching systems used a central controller to directly control which switching network was to be active. This results in the reliability being further reduced.